Objective: To test adherence to blood glucose monitoring (BGM) as a mediator between diabetes-specific family conflict and glycemic control (hemoglobin A(1c) [HbA(1c)] levels) for 1 year.
Design: Three waves of prospective data spanning 1 year.
Setting: Diabetes clinic in a large tertiary care children's hospital in the Midwestern United States.
Participants: One hundred forty-five dyads composed of an adolescent (aged 13-18 years) with type 1 diabetes mellitus and a parent.
Main exposures: Adolescent- and parent-rated diabetes-specific family conflict and mean daily BGM frequency obtained through meter downloads.
Main outcome measure: Levels of HbA(1c), abstracted from the medical record.
Results: In separate general linear models, higher adolescent-rated family conflict scores at baseline predicted less frequent BGM at 6 months (β = -0.08 [P = .01]) and higher HbA(1c) levels at 12 months (β = 0.08 [P = .02]). In the multivariate model including baseline conflict and BGM as predictors of HbA(1c) levels, BGM was a significant predictor (β = -0.24 [P = .007]) and conflict was no longer significant (β = 0.05 [P = .11]), supporting the mediation hypothesis. Post hoc probing showed that BGM explained 24% of the variance in the conflict-HbA(1c) link. The mediation between parent-reported conflict and HbA(1c) levels via BGM adherence was partially supported (conflict predicting HbA(1c) in the zero-order equation, β = -0.24 [P = .004]; multivariate equation, β = 0.06 [P = .02]), and BGM frequency explained 16% of the conflict-HbA(1c) link.
Conclusions: Diabetes-specific family conflict in adolescence predicts deteriorations in BGM and subsequent glycemic control for at least 1 year. Results support ongoing intervention research designed to reduce family conflict and thus prevent a trajectory of declining adherence and glycemic control across adolescence.